Bosch: Electric Cars Will Soon Have Transmissions


Bosch predicts transmissions in electric cars

Most electric cars make so with direct drive – essentially a single “gear” that serves the car from 0 to 100 MPH and beyond. It’s an elegant, simple system that reduces the number of moving parts and lowers costs. If German electronics giant and auto-industry supplier, Bosch, is right, however, that may soon change.

If you have doubts about whether or not that’s a good thing, Go ride a single-speed bicycle for a while before hopping on a 10-speed and you’ll see some of the benefits of adding a little mechanical complexity.

Next, try to remember that when Brammo added a 6-speed transmission to its electric bikes a few years ago, they utterly changed the way electric motorcycles were perceived. Suddenly, the electric motors’ low-end torque advantage over ICEs could be maximized at speed, too.

Two years on, and Brammo is the only electric motorcycle maker to step up and challenge the internal combustion engines’ track day dominance – something that would have been impossible without a conventional multi-speed transmission.

So, good stuff ahead for EVs, then.

According to Bosch’s estimations, sales of electric vehicles will increase to 2.5 million units, globally, by 2020 while plug-in hybrids will also grow in popularity to some 3 million cars. The same report mentions annual sales of conventional (non-PHEV) hybrids will reach 6.5 million by the end of the decade- all of which jives nicely with Nissan-Renault’s estimates, also.

What do you guys think? Is a transmission the way forward for better performance and efficiency, or should the OEMs stick to advancing the state of the battery and energy storage art? Let us know what you think in the comments, below. Enjoy!


Source: Bosch, via WorldCarFans.

About the Author

I've been in the auto industry 1997, and write for a number of blogs in the IM network. You can also find me on Twitter, at my Volvo fansite, or chasing my kids around Oak Park, IL.
  • Steve Hanley

    Formula E uses transmissions. I can’t think of any practical reason NOT to.

    • UncleB

      Mechanical efficiency losses!

    • Complexity adds cost, and often wouldn’t yield a big enough gain in efficiency or range to justify the cost (so sayeth the bean-counters!).

      • AaronD12

        Don’t forget the first Tesla Roadster had a two-speed transmission. After multiple failures, they went to a single-speed reduction gear. Since most EVs use the same setup, I would say it’s probably not worth the extra weight, cost, maintenance, and complexity. I’ll take my EV with a single speed, thank you.

    • Cost, packaging, weight, maintenance/complexity.

      Efficiency is a bit of a mixed bag – you have additional mechanical losses through the gearbox as well as additional rolling resistance due to higher weight, but the operating speed of the motor can be decoupled from the wheel speed. In some cases this can lead to an overall efficiency win.

      Performance is also a mixed bag. Consider a large motor with direct drive versus a smaller motor with a transmission. Maybe we’ll see direct-drive EVs racing multi-gear EVs once Formula E becomes a non-spec series.

      • Steve Hanley

        A thoughtful response. Thank you. Of course, Bosch has a dog in this fight, as they hope to make some money off the transmissions they propose.

        It is going to be very interesting to see how the future of transportation evolves in the next 5 – 10 years.

      • Ed

        Good response, protomech.

        It seems to me that the “advantage” of, say, a two-speed transmission might be a lighter weight motor that could deliver the same torque to the wheels as a larger motor on acceleration, but slow to a more efficient speed (reduced eddy currents and stuff) at higher, cruising speeds. The complexity tradeoff and “experience” difference might not be worth it, of course.

        Another ploy using two front/rear motors might to optimize a rear motor for acceleration and a front motor for cruise. On the highway, the rear motor could be in a “powered idle” mode while the cruise optimized front motor does most of the work. For all I know, Tesla may be doing that on D and X.

        But…ZF hit the news with a press release that suggests “up to 20% improvement” in range, and that has to get everyone’s attention. However, the press release does not state how this is possible. Anyone have some physics on this one? Anyone? Bueller?

  • Turbofroggy

    Multi speed transmissions on an EV is unnecessary and ruins the driving experience of an EV. Multispeed transmissions are just a lame excuse/bandaid fix for manufactures who can’t figure out a good motor/inverter design. ALL production EVs on the road today use a single speed transmission. The only thing that is needed in EVs is bigger/cheaper batteries that are produced in higher numbers, not this shifty transmission BS.

    • That’s not correct – the Brammo is an EV with a 6 speed. MotoCzyz, I believe, also uses a multi-speed trans.

      • MotoCzysz uses a direct-drive approach, as does Brammo for their Empulse RR.

        The production Empulse gearbox doesn’t deliver a compelling performance advantage over its direct drive competition; the Zero SR is quicker, lighter, and more efficient using a slightly larger battery pack and the same motor controller / pack voltage.

        The Empulse has a slightly higher top speed (110 mph vs 102 mph Zero), but with a different gearing combination (say 25 front / 98 rear) the Zero bike’s top speed should increase to ~115 mph, while still accelerating harder than the Empulse.

        • What would you consider a compelling advantage?

          • Lower cost, drivetrain weight and/or volume compared to a similar performance direct-drive system, or a sufficient performance (acceleration or efficiency) advantage to compensate for deficiencies in the former.

            Comparing the Zero SR versus the Brammo Empulse is more complicated than simply comparing the power trains; the Empulse is heavier due in part to the liquid-cooling system and the higher-power J1772 onboard charger, which hurts acceleration despite being very useful features. And likewise, the Zero SR has a slightly larger monolithic battery pack.

            With all that said, the Zero SR has a performance advantage and appears to be slightly more efficient at highway speeds.

            We haven’t seen a direct 2014 Empulse vs 2014 Zero SR professional comparison yet – maybe you can do one? – but here’s what CycleWorld reported in both 2013 (Zero S vs Empulse R) and in 2014 (Zero SR):

            2013 Zero S ZF11.4:
            5.2s 0-60, 14.01s @ 89.7 mph 1/4 mi, 90 mph vmax
            2013 Brammo Empulse R:
            4.8s 0-60, 13.97s @ 90.2 mph 1/4 mi, 103 mph vmax
            2014 Zero SR ZF14.2:
            4.3s 0-60, 13.07s @ 98.6 mph 1/4 mi, 98.7 mph vmax

            Note that they tested the 12.5 kWh battery pack Zero, which weighs 452 pounds, very close to the 2013 Empulse weight of 470 pounds. So weight should be less of a factor for purposes of comparing acceleration.

  • Chris

    IMO what we WILL see is EVs with two motors like the upcoming Model X. The front and rear drivetrains can be geared slightly differently which would effectively give you two speeds with the same EV experience.

    • How would you “gear” a direct drive system?

      • Chris

        Don’t know about the LEAF but Tesla isn’t ‘direct drive’… it’s got a single speed reduction gear… from Tesla website “Single speed fixed gear with 9.73:1 reduction ratio”

  • UncleB

    21st Century Electronic means will reign over the 20th century technologies! Even the ability to switch in more voltage electronically and computer controls all far ahead of anything mechanical!

  • ricksanchez1

    I have to wonder if this is a panic “solution” to a problem that doesn’t yet exist from a supplier worried about their future?

    If a Tesla can go 0-60 in under 5 seconds, have seamless power delivery, and decrease complexity, cost, and weight by NOT including a transmission, what exactly was the reason to integrate one in again?

    • It’s not about 0-60, it’s about 60-130.

      • ricksanchez1

        So you’re saying the transmission option will be called the “Autobahn package?” I mean where is the ROI for a company to design something 95% of the people in the world cannot use on the street?

        • That’s a ridiculous argument, and the thousands of young girls walking around college campuses with Macbook Pros that act as $2000 Facebook machines while 99.95% of Americans own cars that can easily exceed 100 MPH when the speed limit just about everywhere is 70 MPH would have us believe that the ROI is *HUGE*.

          • Offgridman

            What is equally ridiculous is your comparing what kids buy to stay connected to the internet, which is often subsidized or suggested by their schools to what average people buy to drive around on the roads.
            I won’t bother arguing that 99.5% of the vehicles are capable of exceeding 100 mph but will question how many actually abuse their vehicles to attain those speeds? Now granted that many people will actually achieve peaks of 70 or 80, sometimes even 90 mph when driving out on the interstates, in a few areas. But to imagine that the average person will spend the money to have a vehicle that can maintain 100+ mph on a regular basis you are living in a rather elitist world or as the prior commenter said imagining a place where everyone will spend the money to have a car that will show up everyone on the autobahn. Rather than realizing the reality is that most people just need a vehicle that will get them back and forth to work in the rush hour traffic of 40-60 mph.

          • You mean subsidized by the schools that those same kids pay upwards of 6 figures to for the “privilege” of attending? Puh-lease.

  • greenoptimistic

    here’s a blog post on this matter: